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UM1855
Hardware layout and configuration
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In the default configuration of STM32L476G-EVAL, the RX and TX terminals of the LPUART
port are routed to the USB virtual COM port of ST-LINK/V2-1 and, the RX and TX terminals
of USART1 port to the RS-232 connector CN9.
For specific purposes, the TX and RX of the LPUART port of STM32L476ZGT6 can be
routed to the RS-232 connector CN9 instead. As RTS and CTS terminals of CN9 keep
routed to USART1 port, they may block the LPUART communication flow. To avoid this, set
the USART1 hardware flow control off.
The default settings of LPUART are: 115200b/s, 8bits, no parity, 1 stop bit, no flow control.
2.11 microSD
card
The CN18 slot for microSD card is routed to STM32L476ZGT6’s SDIO port, accepting SD
(up to 2 Gbytes), SDHC (up to 32 Gbytes) and SDXC (up to 2 Tbytes) cards. One 4-Gbyte
microSD card is delivered as part of STM32L476G-EVAL. The card insertion switch is
routed to the PA8 GPIO port.
For microSD card operation, the LCD glass module daughterboard must be plugged into
CN11 and CN14 in I/O-bridge position, as explained in
Section 2.15
.
2.11.1 Limitations
Due to the share of SDIO port and PA8 terminals, the following limitations apply:
•
The microSD card cannot be operated simultaneously with LCD glass module or with
motor control.
•
The microSD card insertion cannot be detected when the PA8 is used as
microcontroller clock output (MCO), one of alternate functions of PA8.
2.11.2 Operating
voltage
The supply voltage for STM32L476G-EVAL microSD card operation must be within the
range from 2.7 V to 3.6 V.
Table 10. Hardware settings for LPUART
LPUART port use
R188
R189
R158
R119
R118
JP15 1-2
Default setting
USB virtual COM port of ST-LINK/V2-1
In
In
Out
Out
don’t
care
don’t
care
RS-232 (RX and TX)
Out
Out
In
In
Out
Closed
Table 11. Terminals of CN18 microSD slot
Terminal
Terminal name (MCU port)
Terminal
Terminal name (MCU port)
1
SDIO_D2 (PC10)
6
Vss/GND
2
SDIO_D3 (PC11)
7
SDIO_D0 (PC8)
3
SDIO_CMD (PD2)
8
SDIO_D1 (PC9)
4
VDD
9
GND
5
SDIO_CLK (PC12)
10
MicroSDcard_detect (PA8)
